The invention relates to pressure-sensitive adhesive products for use in adhering to skin or like delicate surfaces.
Pressure-sensitive adhesive tapes and the like are used in a wide variety of applications where there is a need to adhere to skin, for example, medical tapes, wound or surgical dressings, athletic tapes, surgical drapes, or tapes or tabs used in adhering medical devices such as sensors, electrodes, ostomy appliances, or the like. A concern with all these adhesive-coated products is the need to balance the objective of providing sufficiently high levels of adhesion to wet skin as well as to dry skin.
One approach in the art to providing pressure-sensitive tapes for application to wet skin has been the use of pattern coated adhesives. A discontinuous adhesive coating on a backing allows the skin to breathe, at least in the areas of the backing not coated with adhesive. This approach is disclosed in U.S. Pat. Nos. 4,595,001 and 5,613,942, as well as EP 353972 and EP 91800. These patent documents generally teach intermittent coating of adhesives onto different backings. For example, U.S. Pat. No. 5,613,942 describes printing pressure-sensitive adhesives using a release coated calender roll process similar to gravure printing. This patent also teaches screen printing. However, pattern coating or printing of adhesives in this manner is problematic as it generally requires solvents, which are environmentally undesirable. Further, residual low molecular weight species can cause skin irritation. It would be preferred from environmental, manufacturing (e.g., elimination of the need for expensive solvent recovery), and performance perspectives to have adhesives coatable directly from a melt phase.
Articles having good wet skin adhesion are described in U.S. Pat. No. 5,613,942. These articles include a porous backing made of non-wettable fibers and a discontinuously coated adhesive. The backing absorbs less than 4% by weight water, thereby allowing water on wet skin to pass through the entire article. Although this provides suitable wet skin adhesion in some applications, there is still a need for articles having good initial wet skin adhesion in other applications, preferably, on the order of the same article's initial dry skin adhesion.